Expandable TLIF device and related insertion and grafting instrumentation

ABSTRACT

An expandable interbody fusion device and an associated instrument for inserting the device into an intervertebral disc space, expanding the device and for use in delivering graft material into the device once expanded in the disc space. The device is small enough to fit through Kambin&#39;s triangle yet is capable of expanding both in the vertical direction to accommodate spinal lordosis and in the lateral direction to provide sufficient structural support for opposing vertebral bodies laterally within the disc space. A process of forming textured top and bottom surfaces of the device by initially laser ablating each surface with a nano-second pulsed laser followed by laser ablating those surfaces with a femto-second pulsed laser.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 63/127,316, filed Dec. 18, 2020, the entire contents ofwhich are incorporated by reference herein.

FIELD OF THE INVENTION

The subject invention relates generally to the field of spinal implantsand more particularly to an expandable transforaminal interbody fusion(TLIF) device and associated instrumentation for inserting the TLIFdevice into the disc space of a patient and introducing graftingmaterial therein after the device is expanded.

BACKGROUND OF THE INVENTION

Spinal implants such as interbody fusion devices are used to treatdegenerative disc disease and other damages or defects in the spinaldisc between adjacent vertebrae. The disc may be herniated or sufferingfrom a variety of degenerative conditions, such that the anatomicalfunction of the spinal disc is disrupted. Most prevalent surgicaltreatment for these conditions is to fuse the two vertebrae surroundingthe affected disc. In most cases, the entire disc will be removed,except for a portion of the annulus, by way of a discectomy procedure. Aspinal fusion device is then introduced into the intradiscal space andsuitable bone graft or bone substitute material is placed substantiallyin and/or adjacent the device in order to promote fusion between twoadjacent vertebrae.

There are a variety of implants for spinal fusion in current use, someof which are expandable and others of fixed dimension. In order toaccommodate the spinal anatomy and promote arthrodesis, an interbodyfusion device preferably has optimized contact with adjacent endplates.This is commonly achieved by ensuring that the interface between thedevice and the bony endplates of opposing vertebral bodies includes asurface area as large as practicable. Expandable interbody fusiondevices have been particularly used for this purpose. With the advent ofminimally invasive spinal surgery, additional efforts have beenintroduced to further decrease the trauma to the patient during spinalsurgery. In this manner, expandable interbody fusion devices have beensized and configured in a smaller size to be used in a posterolateralapproach through what is known as Kambin's triangle. Smaller sizedinterbody fusion devices typically result in, among other things, asmaller incision, decreased blood loss and shorter patient recovery.Examples of interbody fusion devices sized and configured to fit throughKambin's triangle during introduction into the interbody disc space areshown in U.S. Pat. No. 9,408,717, entitled “Expandable IntervertebralDevice, and Systems and Methods for Inserting Same”, issued on Apr. 9,2016 to Scott J. Perrow, which describes an expandable interbody fusiondevice that expands to increase the height of the disc space, and U.S.Pat. No. 9,844,444, entitled “Far Lateral Spacer”, issued on Dec. 19,2017 to Steve Wolfe et al., which describes an expandable interbodyfusion device that expands laterally within the disc space.

While expandable interbody fusion devices sized and configured to fitthrough Kambin's triangle have certain surgical benefits they raiseother challenges relating to their insertion and the subsequentintroduction of grafting material, particularly due to their relativelysmall size.

Accordingly, there is a need to develop an expandable interbody fusiondevice configured to be used in a transforaminal lumbar interbody fusion(TLIF) procedure that can be inserted into the interbody disc spacethrough Kambin's triangle with suitable insertion and graftinginstruments.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an interbody fusion devicewith improved capability for attachment to an insertion instrument.

It is another object of the invention to provide an improved interbodyfusion apparatus that includes an interbody fusion device and aninstrument attachable to the device for inserting the interbody fusiondevice into an intravertebral disc space,

It is a further object of the invention to provide an improvedinstrument for inserting an interbody fusion device into anintravertebral disc space and for delivering graft material thereto.

It is yet another object of the invention to provide a process offorming textured surfaces on top and bottom surfaces of an interbodyfusion device.

DESCRIPTION OF THE FIGURES

FIG. 1 is an exploded top, front perspective view of an expandableinterbody fusion device and an associated instrument for attachment toand use with the device according to an embodiment of the presentinvention.

FIG. 2 is an enlarged view of FIG. 1 showing the expandable interbodyfusion device and a portion of the distal end of the instrument.

FIG. 3A is a top plan view of the interbody fusion device of FIG. 1.

FIG. 3B is a side elevation view of the interbody fusion device of FIG.1.

FIG. 3C is a rear elevation view of the interbody fusion device of FIG.1

FIG. 3D is a top, rear perspective view of the interbody fusion deviceof FIG. 1

FIG. 3E a cross-sectional view of the interbody fusion device as seenalong viewing lines A-A of FIG. 3A.

FIG. 3F a cross-sectional view of the interbody fusion device as seenalong viewing lines B-B of FIG. 3A.

FIG. 3G a cross-sectional view of the interbody fusion device as seenalong viewing lines C-C of FIG. 3B.

FIG. 4A is a top, front perspective view of the wedge for expanding theinterbody fusion device of FIG. 1.

FIG. 4B is a front elevation view of the wedge of FIG. 4A.

FIG. 4C is a side elevation view of the wedge of FIG. 4A.

FIG. 5 is a further view of the interbody fusion device and distal endof the instrument of FIG. 2 with the distal end of the instrument movedinto alignment with the interbody fusion device for attachment thereto.

FIGS. 6A and 6B are images of the process of attaching the instrument tothe interbody fusion device.

FIG. 7 is an exploded top, front perspective view of the instrument ofFIG. 1.

FIG. 8 is an enlarged exploded view of a portion of the instrument ofFIG. 7.

FIG. 9A is an exploded perspective view of a sectioned portion of theinstrument handle showing details of the locking structure for lockingthe instrument to the interbody fusion device with the locking button ina locked position.

FIG. 9B is a side sectional view of the portion of the instrument handledepicted in FIG. 9A.

FIG. 9C is a longitudinal sectional view of the portion of theinstrument handle depicted in FIG. 9A

FIG. 10A is a further view of FIG. 9A showing the locking button in anunlocked position.

FIG. 10B is a further view of FIG. 9B showing the locking button in anunlocked position.

FIG. 11 is a further view similar to FIG. 10A showing the locking handlemoved to a position allowing the instrument to be separated from theinterbody fusion device.

FIG. 12 is a further view of FIG. 1 showing the interbody fusion deviceand instrument attached with the locking handle in a vertical positionupon attachment.

FIG. 13A is a top, front perspective view of the interbody fusion deviceof FIG. 1 in an expanded condition.

FIG. 13B is a top plan view of the expanded interbody fusion device ofFIG. 10A.

FIG. 13C is a front elevation view of the expanded interbody fusiondevice of FIG. 13A.

FIG. 14 is a further view of FIG. 12 showing a graft delivery cartridgeholding a plurality of graft pellets positioned laterally in theinstrument for individual delivery of graft pellets to the expandedinterbody fusion device.

FIG. 15 is a cross-sectional view of the instrument of FIG. 14 as seenalong viewing lines XV-XV.

FIG. 16 is a top plan view of an unexpanded interbody fusion devicehaving surface texturing in accordance with a particular aspect of thedevice.

DESCRIPTION OF THE EMBODIMENTS

For the purposes of promoting and understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and described in the following written specification. It isunderstood that no limitation to the scope of the invention is therebyintended. It is further understood that the present invention includesany alterations and modifications to the illustrated embodiments andincludes further applications of the principles of the invention aswould normally occur to one skilled in the art to which this inventionpertains.

Referring to FIG. 1, there is shown an expandable interbody fusiondevice 10 and an associated instrument 200 for inserting device 10 intoan intervertebral disc space, expanding device 10 and for use indelivering graft material into device 10 once expanded within the discspace. In accordance with a particular arrangement, device 10 andinstrument 200 are sized and configured for introducing device 10 in aposterolateral approach through Kambin's triangle in a transforaminallumbar interbody fusion (TLIF) procedure. Kambin's triangle is wellknown and is defined as a right triangle over the dorsolateral disc: thehypotenuse is the exiting nerve root, the base (width) is the superiorborder of the caudal vertebra, and the height is the traversing nerveroot, (See M. Hardenbrook et al., “The Anatomic Rationale for theTransforaminal Endoscopic Interbody Fusion: a Cadaveric Analysis”,Neurosurgical Focus Volume 40, February 2016, incorporated herein byreference). As will be described, device 10 is small enough to fitthrough Kambin's triangle yet is capable of expanding both in thevertical direction to accommodate spinal lordosis and in the lateraldirection to provide sufficient structural support for opposingvertebral bodies laterally within the disc space. It should beappreciated that while device 10 is particularly configured for use asspinal implant in a TLIF procedure, it is not limited to use throughKambin's triangle and, as such, may also be used as an expandableinterbody fusion device that may be introduced in other approaches, suchas in the posterior, anterior or lateral directions at different levelsof the spine, or percutaneously.

Turning now to FIGS. 2 and 3A-3G details of expandable interbody fusiondevice 10 are described. Device 10 comprises a cage 12 having a hollowinterior 12 f and a wedge 100 slidable within said hollow interior 12 f.Cage 12 has a distal end 12 a and a proximal end 12 b. Cage 12 isgenerally elongate defining a longitudinal axis 12 c, as depicted inFIG. 3A, extending through distal end 12 a and proximal end 12 b. Wedge100 is sized and configured to be slidably moved within cage 12 toexpand cage 12, as will be described. Cage 12 includes a base 14 at theproximal end 12 b and a plurality of flexibly movable arms 16 projectingfrom base 14 toward distal end 12 a. Arms 16 are free and unattached toeach other at distal end 12 a thereby allowing cage 12 to expand at itsdistal end 12 a. In the arrangement shown, cage 12 has four movable arms16 including a pair of upper arms 16 a and 16 b and a pair of lower arms16 c and 16 d. Arms 16 are attached respectively to base 14 at hingepoints 18 a, 18 b, 18 c (not seen) and 18 d in a manner to allowdeflection of arms 16 relative to base 14 in two transverse directions.Cage 12 further includes a top opening 11 between arms 16 a and 16 b, abottom opening 13 between arms 16 c and 16 d, and a pair of sideopenings, one opening 15 between arms 16 a and 16 c and the otheropening 17 between arms 16 b and 16 d (See also FIGS. 13A and 13B). Inuse, the transverse directions may be mutually orthogonal, namely in avertical direction to expand the device height at distal end 12 a andthereby accommodate lordosis in the disc space, and horizontally toincrease the device width and hence the lateral support of opposingvertebral bodies within the disc space. FIG. 3C shows the unexpandeddevice height H₁ and the unexpanded device width W₁. In a particulararrangement, cage 10 may be formed monolithically as a unitary device tohave a quadrangular shape, as shown in FIG. 3D. It should be understoodthat other cage shapes, such as cylindrical may also be used.

As seen in FIGS. 2 and 3G each of upper arm 16 a and lower arm 16 cincludes an inclined cam surface 20 a and 20 c, respectively facing eachother vertically, for cooperative engagement with wedge 100. Upper arm16 b and lower arm 16 d also include similar inclined cam surfaces 20 band 20 d as shown in FIGS. 2 and 3B that respectively face each othervertically for cooperative engagement with wedge 100. Each of upper arms16 a and 16 b further includes an inclined cam surface 22 a and 22 b asshown in FIG. 3A, respectively facing each other laterally, forcooperative engagement with wedge 100. Each of lower arms 16 c and 16 dalso include similar inclined cam surfaces 22 c and 22 d as shown inFIG. 3G that face each other laterally for cooperative engagement withwedge 100. Each of lower arms 16 c and 16 d additionally includes alocking notch 23 c and 23 d as shown in FIG. 3G, while each of upperarms 16 a and 16 b additionally includes a locking notch 23 a (not seen)and 23 b, shown in FIG. 3B. Locking notches 23 a, 23 b, 23 c and 23 d,are each disposed adjacent distal end 12 a of cage 12 for receipt ofportions of wedge 100 to lock the plurality of arms 16 in the expandedposition of cage 12.

Referring now to FIGS. 4A-4C details of wedge 100 are described. Wedge100 serves as an expander of device 10 and is sized and configured to bemovably contained within cage 12 to expand the distal end 12 a of cage12 upon distal movement. Wedge 100 is generally cruciform in shape andhas a threaded hole 101 extending generally centrally therethrough forthreaded engagement with a threaded shaft of instrument 200, as will bedescribed. Wedge 100 has a vertical section 102 and a transversehorizontal section 104 that in a particular arrangement lie mutuallyorthogonal to each other. Vertical section 102 has angled side surfaces102 a and 102 b formed above horizontal section 104 and angled sidesurfaces 102 c and 102 d formed below horizontal section 104. Duringmovement of wedge 100 in cage 12 toward distal end 12 a, curved sidesurfaces 102 a and 102 b are arranged to respectively engage inclinedcam surfaces 22 a and 22 b on upper arms 16 a and 16 b as shown in FIG.3A, while angled side surfaces 102 c and 102 d are arranged torespectively engage inclined cam surfaces 22 c and 22 d on lower arms 16c and 16 d. Such movement of wedge 100 and cooperative engagement withcage 12 will cause each of the distal ends of arms 16 a, 16 b, 16 c and16 d to deflect laterally away from centerline 12 c in a cantileveredmanner about hinge points 18 a, 18 b, 18 c and 18 d to thereby expandthe width of cage 12 at distal end 12 a.

Horizontal section 104 has curved upper surfaces 104 a and 104 b formedon opposite lateral sides of vertical section 102 above horizontalsection 104 and curved lower surfaces 104 c and 104 d formed on oppositelateral sides of vertical section 102 below horizontal section 104. Assuch, during movement of wedge 100 in cage 12 toward distal end 12 a,curved upper surfaces 104 b is arranged to engage inclined cam surface20 b on upper arms 16 b while curved lower surface 104 d is arranged toengage inclined cam surface 20 d on lower arm 16 d, as shown in FIG. 3B.Similarly, curved upper surfaces 104 a is arranged to engage inclinedcam surface 20 a on upper arm 16 a while curved lower surface 104 c isarranged to engage inclined cam surface 20 c on lower arm 16 c. Suchmovement of wedge 100 and cooperative engagement with cage 12 will causeeach of the distal ends of arms 16 a, 16 b, 16 c and 16 d to deflectvertically away from centerline 12 c in a cantilevered manner abouthinge points 18 a, 18 b, 18 c and 18 d to thereby expand the height ofcage 12 at distal end 12 a. In addition, each of curved upper surfaces104 a and 104 b terminate respectively in an engagement edge 106 a and106 b while each of curved lower surfaces 104 c and 104 d terminaterespectively in an engagement edge 106 c and 106 d. Engagement edges areconfigured to engage and reside in respective locking notches 23 a, 23b, 23 c and 23 d to lock cage 12 in the expanded position, as will bedescribed.

In a particular arrangement, wedge 100 and inclined cam surfaces 20 a-dand 22 a-d on arms 16 a-d are configured and oriented in manner to causesimultaneous movement of the plurality of arms 16. It should beappreciated that inclined surfaces 20 a-d and 22 a-d may also beconfigured and oriented relative to wedge 100 to cause sequentialmovement whereby the plurality of arms 16 are first moved in a lateraldirection followed by movement in a vertical direction, or vice versa asdesired.

Cage 12 and wedge 100 are both formed of suitable metallic or polymericbiomaterials. Suitable biocompatible metallic materials include puretitanium, tantalum, cobalt-chromium alloys, titanium alloys (e.g.,nickel titanium alloys and tungsten titanium alloys), stainless steelalloys, molybdenum rhenium (MoRe), and NiTinol (for superelasticproperties). Suitable polymeric materials include members of thepolyaryletherketone (PAEK) family, e.g., polyetheretherketone (PEEK),carbon-reinforced PEEK, polyetherketoneketone (PEKK); polysulfone;polyetherimide; polyimide; ultra-high molecular weight polyethylene(UHMWPE); or cross-linked UHMWPE. Ceramic materials such as aluminumoxide or alumina, zirconium oxide or zirconia, compact of particulatediamond, or pyrolytic carbon may be included in such polymers. It shouldbe appreciated that these materials may be used independently or in acomposite arrangement, as desired.

Referring again to FIGS. 3C, 3D, 3E and 3F, and also to FIG. 5, detailsof the attachment of expandable interbody fusion device 10 andinstrument 200 are described. As noted above, in a particulararrangement, device 10 is sized and configured to fit into anintradiscal space through Kambin's triangle. As a result, thecross-sectional profile of device 10 as defined by its height and widthis dimensioned in a manner to allow use through Kambin's triangle. Inaddition, since at least the distal end of the instrument 200 forinserting device 10 may also need to fit through Kambin's triangle, thedimensions of the distal end of instrument 200, including an attachmentend 202, are likewise configured to be consistent with introductionthrough Kambin's triangle. In this manner, instrument 200 is configuredto attach to proximal end 12 b of cage 12 with at least the distal endof instrument 200 having a maximum dimension within the confines of theouter cross-sectional profile of cage 12.

While the size of the outer cross-sectional profile of cage 12 isconfigured as small as practicable for introduction through Kambin'striangle, the open interior configuration of cage 12 is desirably aslarge as practicable to facilitate subsequent introduction of graftmaterial into expanded cage 12. As an example, when sized and configuredfor a TLIF fusion procedure at the L1/L2 lumbar level, the unexpandedheight H₁ of cage 12 as shown in FIG. 3C may be 8.0 mm with theunexpanded width W₁ being 8.5 mm. As so dimensioned in this example, theouter cross-sectional profile is nearly square. To maximize graft entryinto cage 12, an inner graft circular opening 24 may be provided to havea diameter of up to about 5.0 mm. As so dimensioned, the ratio of thegraft opening area to the cross-sectional area of cage 12 is at least aminimum of approximately 29%. While these dimensions and minimum graftopening ratio are desirable for graft delivery, such dimensions leaverelatively little material for attachment of cage 12 to instrument 200in either the height or width directions. Accordingly, opposite diagonalcorners 12 d as seen in FIG. 3C are used for purposes of attachment ofcage 12 to instrument 200.

FIG. 5 illustrates attachment portion 202 of instrument 200 oriented ina position ready for secured attachment to cage 12. Instrument 200,which will be described in further detail below, includes an outer tube204 that supports a rotatable cylindrical inner tube 206. In aparticular arrangement, outer tube 204 may have a rectangularcross-section not greater in size than the cross-section of theunexpanded cage 12. Inner tube 206 includes attachment portion 202 atits distal end. Attachment portion 202 comprises a pair of lugs 208 thatproject radially outwardly from inner tube 206 in diametrically oppositedirections. As illustrated also in FIG. 3D, cage 12 comprises aninstrument attachment feature 13 at base 14 that includes an outer wall26 at proximal end 12 b and an inner wall 28 spaced interiorly of outerwall 26. Inner wall 28 includes graft opening 24 in communication withcage hollow interior 12 f. Outer wall 26 includes an entrance opening 30that is in communication with graft opening 24 and cage hollow interior12 f. Entrance opening 30 has a configuration different from theconfiguration of graft opening 24 and in a particular arrangement has acircular portion 30 a and a pair of arcuate lobes 30 b that projectradially outwardly from circular portion 30 a in diametrically oppositedirections. Lobes 30 b are arranged to be disposed along a diagonal axis12 e that extends toward opposite corners 12 d of cage 12 as illustratedin FIG. 3C. Axis 12 e in this arrangement lies at an acute angle withrespect to both the height and width of cage 12. Circular portion 30 aof entrance opening 30 is sized to relatively closely receivecylindrical inner tube 206 of instrument 200, while lobes 30 b are sizedto relatively closely receive respective lugs 208 on inner cylindricalinner tube 206. While attachment portion 202 of instrument 200 can bereceived through entrance opening 30, graft opening 24 is sized to be oflesser dimension than circular portion 30 a of entrance opening 30, andas such, attachment portion 202 of instrument 200 cannot pass throughgraft opening 24 of inner wall 28.

While entrance opening 30 is formed in one arrangement to have acircular portion with oppositely projecting lobes, it should beappreciated that other shapes of entrance opening 30 may also beprovided. For example, entrance opening 30 may be formed in the shape ofan oval or other shapes having a longer extent along diagonal axis 12 eand a shorter extent transverse thereto.

The space between outer wall 26 and inner wall 28 defines a lockingpocket 32 as depicted in FIGS. 3D and 3F. Locking pocket 32 has acircular portion 32 a that is configured to receive cylindrical innertube 206 of instrument 200 and a pair of extended lobes 32 b that extendradially outwardly from circular portion 32 a. Extended lobes 32 b areconfigured to have a greater arcuate extent along the circumference ofcircular portion 32 a than lobes 30 b of entrance opening 30. As such,extended lobes 32 b communicate in alignment with lobes 30 b for anarcuate portion and extend arcuately further not in alignment with lobes330 b behind outer wall 26. Accordingly, once extended through entranceopening 30 as shown in FIG. 6A inner tube 206 may be rotated at asuitable angle, such that lugs 208 are arcuately moved within extendedlobes 32 b until lugs 208 reside between inner wall 28 and outer wall26, as shown in FIG. 6B. In the particular example of the cage 12 havingan unexpanded height H₁ of 8.0 mm and a width W₁ of 8.5 mm, inner tube206 may be rotated approximately 41° to move lugs 208 in positionbetween inner wall 28 and outer wall 28. Points 32 c at the transitionof circular portion 32 a and extended lobes 32 b as shown in FIG. 3F mayserve as mechanical stops upon engagement by lugs 208 to prevent furtherrotation of attachment portion 202 within locking pocket 32. In thisposition attachment portion 202 may not be withdrawn from cage 12 andcan be securely locked to cage 12, as will be described.

Turning now to FIGS. 7 and 8 further details of instrument 200 aredescribed. Instrument 200 includes an elongate instrument handle 210,outer tube 204, inner tube 206 and wedge driver 212. As described, outertube 204 may have at its distal end 204 a a rectangular cross-sectionnot greater in size than the cross-section of the unexpanded cage 12.The remaining extent of outer tube 204 may have a cylindrical outersurface 204 c. Outer tube 204 has an interior lumen 204 b extendinglongitudinally therethrough. Inner tube 206 includes attachment portion202 at distal end 206 a that comprises the pair of lugs 208 as describedabove. Inner tube 206 has a cylindrical exterior surface 206 d forsliding engagement within lumen 204 b of outer tube 204. Inner tube 206has an interior lumen 206 b extending longitudinally therethrough. Alocking handle 214 is included at the proximal end 206 c of inner tube206. Locking handle 214 is fixedly secured to inner tube 206 forrotational and axial movement therewith and includes a radiallyprojecting shaft 214 a terminating in a locking lever 214 b thatfacilitates manual rotation of locking handle 214 and hence inner tube206, as will be described.

Wedge driver 212 comprises an elongate cylindrical shaft 212 a having adistal end 212 b and a proximal end 212 c. Cylindrical shaft 212 a issized and configured to extend slidingly into lumen 206 b of inner tube206. A threaded portion 212 d is included at the distal end 212 b ofshaft 212 a, threaded portion 212 d being configured to threadablyengage threaded hole 101 of wedge 100, as will be described. An enlargedcylindrical portion 212 e is disposed at the proximal end 212 c of wedgedriver 212.

Referring particularly now also to FIG. 8, handle 210 comprises a handlebody 210 a, a handle cover 210 b, and an end cap 211. Handle cover 210 bis suitably attached to handle body 210 a by fastening members, such asset of four screws 216. End cap 211 is suitably attached to handle body210 a and may be oriented by a key 213 formed at the proximal end ofhandle body 210 a. Handle 210 fixedly supports outer tube 204 at itsdistal end and includes a channel 210 c adjacent its distal end forreceipt and support of inner tube 206. An opening 211 a extends throughend cap 211 in alignment with an opening 210 d through the proximal endof handle body 210 a for receipt of a portion of a T-handle to drivewedge driver 212 axially distally, as will be described. A cammingelement 218 is supported in a pocket 220 defined by ledges 222 and 224at the distal end of handle body 210 a. Camming element 218 has anangled cam surface 218 a facing proximally for interaction with camsurface 214 c of locking handle 214 (See FIGS. 9B and 10B) as will bedescribed. Camming element 218 may be secured within pocket 220 bysuitable fastening members, such as screws 226 and 228. Handle body 210a supports a depressible locking button 230 adjacent the distal end ofhandle body 210 a for pivotal movement within handle body 210 a. Lockingbutton 230 may be spring biased by a compression spring 232 captured ina recess 210 e that normally biases locking button 230 in the lockingposition, as will be described. Handle body 210 a also includes adjacentcamming element 218 an opening 234 configured and sized to receive shaft214 a of locking handle 214 therein for limited rotational movementrelative to handle body 210 a. Handle body 210 a further supports adrive nut 236. Drive nut 236 may have a substantially rectangularconfiguration for receipt and retention in a compatible rectangularrecess 238 formed interiorly of handle body 210 a. With handle cover 210b attached to handle body 210 a drive nut 236 is suitably retainedwithin handle 210 and is prevented from either axial or rotationalmovement therein. Drive nut 236 in a particular arrangement includesinterior threads 236 a for engagement with a suitable tool to drivewedge driver 212 and hence wedge 100 axially distally to expand cage 12,as will be described. A relatively flat surface 240 may be formed at theproximal end of handle end cap 211 to allow slight impaction forassisting the insertion of interbody fusion device 10 into the discspace.

Referring still to FIGS. 7 and 8, in a particular aspect, handle 210 ofinstrument 200 may be formed to receive a grafting cartridge tofacilitate the introduction of graft material into an expanded device10, as will be further described. In this regard, handle body 210 a andhandle cover 210 b are formed to have side openings 215 and 217,respectively for lateral receipt of a cartridge that contains graftmaterial. A movably releasable detent 242 that may be manually overcomeupon lateral force to the cartridge may be supported in a recess 244within handle body 210 a.

Turning now to FIGS. 9A-9C, 10A-10B and 11, further details and functionof the locking button 230 are described. FIGS. 9A-9C show the lockingbutton 230 in a normally locked position. Locking button 230 isrotatably supported within handle 210 by a pivot pin 246. Locking button230 includes a depressible portion 230 a at one end and a projectinglock 230 b at the opposite end. Depressible portion 230 may be ofcircular configuration or other suitable shape and is accessible to theuser through opening 248 in handle 210. In the position shown in FIGS.9A, 9B and 9C, biasing spring 232 urges depressible portion 230 adownwardly and thereby urges lock 230 b upwardly causing a free end 230c of lock 230 b to enter a locking groove 214 d in locking handle 214.FIGS. 10A and 10B show the locking button 230 in a released position.The user may manually push depressible portion 230 a upwardly causinglock 230 b at the opposite end to move downwardly, thereby moving freeend 230 c of lock 230 b out from locking groove 214 d of locking handle214. In this position locking handle 214 may freely rotate within handleopening 234 as shown in FIG. 11, thereby causing rotation of inner shaft206 relative to handle 210. In this position, free end 230 d of lock 230b may reside in a secondary groove 214 e in locking handle 214 that maybe overcome upon rotating locking handle 214 back to the lockedposition. The position of locking handle 214 in FIG. 11 is the same asthe locking handle 214 as shown in FIG. 1.

Having described the details of interbody fusion device 10 andinstrument 200, use of instrument 200 to insert device 10 into a discspace between two opposing vertebral bodies, expand device 10 thereinand facilitate graft delivery into expanded device 10 is now described.An incision is made through tissue of a patient to establish a workingcorridor to the spinal surgical site, for example, through Kambin'striangle, for a TLIF procedure. The corridor may be formed with suitableinstruments and the disc space may be suitably prepared through thecorridor for insertion of interbody fusion device 10. Instrument 200,without wedge driver 212, may be attached to device 10 by initiallyaligning lugs 208 at attachment end 202 of inner tube 206 with lobes 30b of opening 30 at outer wall 26 of cage 12, as depicted in FIG. 2.Attachment end 202 may then be inserted into cage 12 through opening 30as illustrated in FIG. 5 and into locking pocket 32 with lugs 208 beingsituated within extended lobes 32 b, as shown in FIG. 6A. At this point,locking handle 214 is in an angular position relative to handle 210 asshown in FIG. 1. Locking handle 214 is then rotated manually in aclockwise direction looking from the proximal end of instrument 200toward the patient until handle 214 is in the vertical position as shownin FIGS. 9A-9C and 12. Structural features, such as projections 204 d(see FIGS. 2 and 5) at the distal end of outer tube 204 enter and engagethe lobes 30 b at the proximal end of device 10 to prevent relativerotation between outer tube 204 and device 10 during rotation of lockinghandle 214. In the above example of a cage 12 having an unexpandedheight H₁ of 8.0 mm and a width W₁ of 8.5 mm, locking handle 214 may berotated approximately 41°. During rotation of locking handle 214 to thevertical position, shaft 214 a of locking handle 214 engages lockingbutton 230 and pushes locking button 230 axially proximally against thebias of spring 232. As locking handle 214 reaches the vertical positionshown in FIG. 12 free end 230 c is moved out from secondary grove 214 eof locking handle 214 allowing locking button 230 to snap free end 230 cof lock 230 b into locking grove 214 d to thereby lock locking handle214 in such position until locking button 230 is manually depressedupwardly relative to handle 210.

During such rotation of locking handle 214 lugs 208 are moved arcuatelyto extend into extended lobes 32 b behind outer wall 26, as illustratedin FIG. 6B. In this position, proximal wall 26 is captured between lobes208 and the distal end 204 a of outer tube 204 of instrument 200.Simultaneously during such rotation cam surface 214 c on locking handle214 slidingly engages cam surface 218 a on camming element 218 causinginner tube 206, which is securely affixed to locking handle 214, to moveslightly axially proximally relative to handle 210. The amount of axialproximal movement of inner tube 206 is sufficient to cause outer wall 26to be sandwiched between lobes 208 at the distal end of inner tube 206and the distal end 204 a of outer tube 204. Upon locking handle 214reaching the vertical position shown in FIG. 12 sufficient compressionforce is applied to outer wall 26 to securely tighten instrument 200 tocage 12 of device 10.

Upon attachment of instrument 200 to cage 12 instrument 200 is used toinsert device 10 into the suitably prepared disc space. Flat surface 240of instrument handle 210 may be appropriately tapped or malleted togently urge device 10 into the disc space, if desired by the surgeon.Wedge driver 212 is then introduced into lumen 206 b of inner tube 206and threaded portion 212 d is manually threaded into threaded hole 101of wedge 100 to suitably attach wedge 100 to wedge driver 212. Wedgedriver 212 may alternatively in accordance with the surgeon's practicebe attached to wedge 100 prior to introduction of device 10 into thedisc space. Once attached, wedge driver 212 may be suitably drivenaxially distally to push wedge 100 axially distally within cage 12 toexpand cage 12 within the disc space as described above. Wedge 100 whichis initially disposed approximately centrally between distal end 12 aand proximal end 12 b of cage 12 is moved toward distal end 12 a untilengagement edges 106 a, 106 b, 106 c and 106 d engage and reside inrespective locking notches 23 a, 23 b, 23 c and 23 d to lock cage 12 inthe expanded position as shown in FIG. 13A

A suitable tool to drive wedge driver 212 and hence wedge 100 axiallymay be a T-handle (not shown). Such a T-handle may have an elongatecylindrical tube that has external threads at a distal end. T-handle maybe configured such that the cylindrical tube slides within opening 211 aof handle end cap 211 until the external threads at the distal end ofthe T-handle are threadably received within interior threads 236 a ofdrive nut 236. An interior transverse surface may be provided withinT-handle to engage enlarged cylindrical portion 212 e at the proximalend 212 c of wedge driver 212. Suitable rotation of T-handle will causeT-handle to move axially distally relative to handle 210 under theinfluence of the threaded engagement between external threads of theT-handle and interior threads 236 a of drive nut 236, causing interiortransverse surface of T-handle to push against enlarged cylindricalportion 212 e and thereby push wedge driver 212 axially in the distaldirection. Such rotation of T-handle is continued until cage 12 isproperly expanded as shown in FIGS. 13A-13C and wedge 100 is suitablylocked within locking notches 23 a-d.

After interbody fusion device 10 is expanded, wedge driver 212 and, ifused, the T-handle, may be removed from instrument 200, which remainsattached to expanded device 10. Graft material may be introduced intoexpanded interbody fusion device 10 using instrument 200. As shown inFIGS. 14 and 15, an elongate cartridge 300 containing a plurality ofindividually spaced pellets 302 of graft material may be slidinglyinserted into opening 215 in the side of instrument handle 210 asillustrated in FIG. 14. Cartridge 300 may contain any suitable number ofindividual pellets 302, with five pellets being shown in FIG. 15.Cartridge 300 includes a plurality of recesses 304, each of which isassociated and aligned with one of the individual pellets 302. Eachrecess 304 is configured to receive movably releasable detent 242 asdepicted in FIG. 15. Receipt of detent 242 into a respective recess 304tentatively holds cartridge 300 in a position such that one of thepellets is aligned with interior lumens 206 b and 204 b of inner tube206 and outer tube 204, respectively. As a manual force is appliedagainst cartridge 300 in the lateral direction, the tentative positionis overcome as detent 242 is moved transversely out from a respectiverecess 304 allowing cartridge 300 to move further into handle 210 untilanother recess 304 is aligned with detent 242. Cartridge 300 may bemoved laterally through handle 210 until it emerges through opening 217on the opposite side of handle 210, at which time it may be removed. Aseach pellet 302 is aligned with inner tube 206 and outer tube 204, asuitable plunger 250 may be introduced through opening 211 a of handleend cap 211 to push pellets 302 individually one at a time through graftopening 24 into interior hollow 12 f of expanded interbody device 10until sufficient graft material has been placed. As noted above, graftopening 24 of cage 12 of interbody fusion device 10 may in someinstances be provided to have a diameter of up to about 5.0 mm, whichfacilitates an effective and easy delivery of a suitable quantity ofgraft material. As graft material fills interior hollow 12 f graftmaterial may further pass through cage top opening 11 and bottom opening13 to make contact with the endplates of opposing vertebral bodies of aspine to facilitate fusion thereto. Graft material may also emanate fromcage side openings 15 and 17 so as to occupy the intervertebral spaceadjacent cage 12 to promote additional fusion to the opposing vertebralbodies.

As an alternative, a separate graft delivery device may be used inconjunction with instrument 200 to deliver an appropriate amount ofgraft material to the surgical site and into expanded device 10. Onesuch suitable graft delivery device is described in U.S. Pat. No.10,492,925, issued on Dec. 3, 2019 to Hollister et al. (the '925 Patent)and assigned to the same assignee as the subject application. The entirecontents of the '925 Patent are incorporated herein by reference. Thegraft delivery device described in the '925 Patent is commerciallyavailable under the brand name GraftMag. In use, the channel 12described in the '925 Patent made be introduced through inner tube 206of instrument 200 to place graft into device 10 through opening 30 ofcage 12.

Upon delivery of suitable graft material and completion of the surgicalprocedure, instrument 200 may then be detached from the expanded cage12. To effect such detachment depressible portion 230 a of lockingbutton 230 is manually depressed upwardly releasing lock 230 b fromlocking groove 214 d as described hereinabove thereby allowing lockinghandle 214 to move radially within opening 234 of handle 210 to theangular position shown in FIG. 1. During such movement, the compressionof cage outer wall 26 between lugs 208 and the distal end 204 a ofinstrument outer tube 204 is loosened while lugs 208 are radially movedback into alignment with lobes 30 b. At this point, instrument 200 maybe withdrawn from expanded device 10 and from the surgical site.

In the example provided above for use in a TLIF fusion procedure at theL1/L2 lumbar level, cage 12 may have an unexpanded height H₁ of 8.0 mmand an unexpanded width W₁ of 8.5 mm. Upon expansion, distal end 12 a ofcage may be increased to an expanded height H₂ of 10 mm and an expandedwidth W₂ of 11 mm, as shown in FIGS. 13A, 13B and 13C. The increase inheight to H₂ results in a lordotic angle of eight degrees at distal end12 a and an increase in the width of cage 12 at distal end 12 a ofapproximately 29%. As noted above, interbody fusion device 10 may alsobe used in TLIF fusion procedures at other spinal levels. For example,cage 12 when used in a TLIF fusion procedure at the L4/L5 level may havean unexpanded height H₁ of 16.0 mm and an unexpanded width W₁ of 8.5 mmconsistent with introduction through Kambin's triangle. Upon expansion,distal end 12 a of cage 12 at this level may be increased to an expandedheight H₂ of 18 mm resulting in a lordotic angle of eight degrees and anexpanded width W₂ of 11 mm. At such other level, cage 12 may have anopening 30 at the proximal end 12 b of 5.0 mm to be compatible with thegraft delivery instruments, although other suitable dimensions foropening 30 may be used.

Turning now to FIG. 16, a cage 112 that is a variation of cage 12 isshown. Cage 112 is identical to cage 12 except for the provision oftextured top and bottom surfaces. Since the texturing of both top andbottom surfaces are the same, only the details of top textured surfaceare shown and described, it being understood that the details of bottomtextured surface are the same. Textured top surface 34 is formed on bothupper arms 16 a and 16 b. As shown, textured top surface 34 is formed onthe entire top surface 34 of upper arms 16 a and 16 b. In someinstances, texturing may be included only on those portions that areconfigured to contact a vertebral endplate of a superior vertebral bodyadjacent the disc space. The textured surface includes those upperportions of arms 16 a and 16 b that have fixation structures, such as aplurality of serrations 36. Such serrations 36 are not included adjacenthinge points 18 a and 18 b. In other instances, no textured surfaces maybe formed at the distal end 12 a of cage 112 that is curved in a mannerto facilitate entrance of cage 112 into the disc space.

Textured surface 34 may be formed in a three-dimensional geometricpattern having a plurality of projections and recesses. Such a patternmay be formed by various methods, including without limitation, laserablation, acid etching and machining. Textured surfaces in such apattern are believed to promote the formation of intimate tissueintegration between the endplates of the opposing vertebral bodies andcage 112. In a particular arrangement where cage 112 is formed oftitanium, textured surface 34 may be formed by ablating the upper andlower surfaces of cage 112 by a pulsed laser in the nanosecond range tocreate a porous surface comprising projections and recesses having adepth of up to at least 100 μm. Such a process may be performed inaccordance with the nanosecond laser devices and methods taught anddescribed, for example, in U.S. Pat. No. 5,473,138, entitled “Method forIncreasing the Surface Area of Ceramics, Metals and Composites”, issuedto Singh et al on Dec. 5, 1995, the entire contents of which areincorporated herein by reference.

In an effort to further enhance the tissue integration aspects of cage112, textured upper surface 34 may be subsequently treated by furtherablating those previously formed surfaces by an ultrafast pulsed laserto create additional, smaller projections and recesses having a depthless than 1 μm and preferably not greater than 200 nm. Such a processmay be performed with a picosecond pulsed laser or a femtosecond pulsedlaser device in accordance with, for example, the methods and laserdevices taught and described in U.S. Pat. No. 6,951,627, entitled“Method of Drilling Holes With Precision Laser Micromachining”, issuedOctober 2005 to Li et al., the entire contents of which are incorporatedby reference herein. Other picosecond and femtosecond pulsed lasers mayalso be used, such as those described in U.S. Pat. No. 10,603,093,entitled “Bone Implant and Manufacturing Method Thereof”, issued on Mar.31, 2020 to Lin et al., the contents of which are incorporated byreference in their entirety. In a particularly preferred arrangement,textured surface 34 is formed by initially laser ablating the surfacesof cage 112 with the nanosecond laser devices to form a porous surfacefollowed by laser ablation with the femtosecond laser to further alterthe surface to produce nano-scale structures.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same should be considered asillustrative and not restrictive in character. For example, theinventive concepts described herein may be used with non-expandable aswell as expandable spinal implants, and the textured surfaces formed bythe laser ablation processes described herein may also be used withother spinal implants and in spinal surgical procedures other than TLIFapplications. Accordingly, it is understood that only the preferredembodiments have been presented and that all changes, modifications andfurther applications that come within the spirit of the invention aredesired to be protected.

What is claimed is:
 1. An interbody fusion device, comprising: a cagehaving a distal end, a proximal end, a base at the proximal end, and ahollow interior accessible through said base, said cage comprising aninstrument attachment feature at said base including an outer wall atthe proximal end of said cage and an inner wall spaced interiorly fromsaid outer wall and defining therebetween a locking pocket, said innerwall having a first opening and said outer wall having a second opening,said first opening and said second opening being in communication withsaid hollow interior of said cage, said first opening being of lesserdimension than said second opening, said locking pocket having an extentextending behind a portion of said outer wall.
 2. The interbody fusiondevice of claim 1, wherein said cage has a height and a width thatintersect and define four corners of said cage, opposing diagonalcorners defining an axis that lies at an acute angle with respect toboth said height and said width.
 3. The interbody fusion device of claim2, wherein said second opening has a first extent that is longer alongsaid axis and a second extent that is shorter in a direction transverseto said axis.
 4. The interbody fusion device of claim 3, wherein thesecond opening has a circular portion and a pair of arcuate lobesextending radially therefrom in opposite directions along said axis,said arcuate lobes defining said longer first extent along said axis andsaid circular portion defining said shorter extent.
 5. The interbodyfusion device of claim 4, wherein said locking pocket has a circularportion aligned with said circular portion of said second opening and apair of extended lobes extending radially therefrom in oppositedirections along said axis, said extended lobes being in communicationwith said lobes of said second opening for an arcuate portion andextending for a further arcuate portion beyond said lobes of said secondopening to a location behind said portion of said outer wall.
 6. Theinterbody fusion device of claim 5, wherein said first opening defines agraft opening having a circular configuration, and wherein said heightand said width of said cage define a cross-sectional area of said cage,said graft opening having an area that is no less than 29% of thecross-sectional area of said cage.
 7. The interbody fusion device ofclaim 2, wherein said cage is configured to be expandable.
 8. Theinterbody fusion device of claim 7, wherein said cage is configured tobe expandable in both the height and width directions.
 9. The interbodyfusion device of claim 8, wherein said cage comprises four movable armshingedly attached to said cage at said base.
 10. The interbody fusiondevice of claim 9, wherein said arms of said cage are deflectedoutwardly at the distal end of said cage in the height direction andwidth direction by a wedge that is movable within said cage towards saiddistal end.
 11. The interbody fusion device of claim 10, wherein saidcage is dimensioned in an unexpanded condition to be introduced into anintravertebral disc space in a posterolateral approach through Kambin'striangle for a transforaminal lumbar interbody fusion (TLIF) procedure.12. The interbody fusion device of claim 11, wherein an unexpandedheight of said cage for a TLIF procedure at the L1/L2 lumbar level isabout 8.0 mm.
 13. The interbody fusion device of claim 11, wherein anunexpanded height of said cage for a TLIF procedure at the L4/L5 lumbarlevel is about 16.0 mm.
 14. The interbody fusion device of claim 11,wherein an unexpanded width of said cage for a TLIF procedure is about8.5 mm.
 15. The interbody fusion device of claim 1, wherein said cagehas a top surface and an opposite bottom surface, said top surface andsaid bottom surface comprising textured surfaces.
 16. The interbodyfusion device of claim 15, wherein said cage is formed of titanium. 17.An interbody fusion device, comprising: a cage having a distal end, aproximal end, a base at the proximal end, and a hollow interioraccessible through said base, said cage comprising an instrumentattachment feature at said base including an outer wall at the proximalend of said cage having an attachment opening therethrough incommunication with said hollow interior of said cage, said cage having aheight and a width that intersect to define four corners of said cage,opposing diagonal corners defining an axis that lies at an acute anglewith respect to both said height and said width, said attachment openinghaving a first extent that is longer along said axis and a second extentthat is shorter in a direction transverse to said axis.
 18. Theinterbody fusion device of claim 17, wherein the attachment opening hasa circular portion and a pair of arcuate lobes extending radiallytherefrom in opposite directions along said axis, said arcuate lobesdefining said longer first extent along said axis and said circularportion defining said shorter extent.
 19. The interbody fusion device ofclaim 18, wherein said cage is configured to be expandable.
 20. Theinterbody fusion device of claim 19, wherein said cage is configured tobe expandable in both the height and width directions.
 21. The interbodyfusion device of claim 20, wherein said cage comprises four movable armshingedly attached to said cage at said base.
 22. The interbody fusiondevice of claim 21, wherein said arms of said cage are deflectedoutwardly at the distal end of said cage in the height direction andwidth direction by a wedge that is movable within said cage towards saiddistal end.
 23. The interbody fusion device of claim 22, wherein saidcage is dimensioned in an unexpanded condition to be introduced into anintravertebral disc space in a posterolateral approach through Kambin'striangle for a transforaminal lumbar interbody fusion (TLIF) procedure.24. The interbody fusion device of claim 17, wherein said cage has a topsurface and an opposite bottom surface, said top surface and said bottomsurface comprising textured surfaces.
 25. The interbody fusion device ofclaim 24, wherein said cage is formed of titanium.
 26. The interbodyfusion device of claim 17, wherein said instrument attachment feature atsaid base includes an inner wall spaced interiorly from said outer wall,said inner wall having a graft opening therethrough in communicationwith said attachment opening and said hollow interior of said cage, saidinner wall defining with said outer wall a locking pocket therebetweenthat is configured for receipt of a portion of an instrument attachableto said cage.
 27. The interbody fusion device of claim 26, wherein saidgraft opening is of lesser dimension than said attachment opening.